Electrical conductor



H. H. GLENN ELECTRICAL CONDUCTOR Filed Sept. 22, 1921 Lit) Patented Nov.9, 1926.

UNITED STATES HOWARD H. GLENN, OF WESTFIELD, NEW JERSEY, ASSIGNOR TOWESTERN ELECTRIC 1,666,166 PATENT OFFICE.

COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

ELECTRICAL CONDUCTOR.

Application led September 22, 1921. Serial No. 502,423.

This invention relates in general to electric conductors andparticularly to a flexible shielded conductor.

In view of the increasing use of electrical currents of high frequencythere is an increasing necessity for shielding conductors in such amanner as to prevent interference from extraneous magnetic fields. Inapparatus used under such conditions it has been the common practice toshield the conductors by placing them within a lead tube or sheathingwhich may be easily bent to conform with the desired path of theconductor. The apparatus is, Where possible, provided with metallicshields which are grounded so as to drain ofi' any potentials inducedtherein. However, in the case of flexible conductors, such as receivercords for example. it has heretofore been difficult to provide thedesired degree of shielding and it is an object of the present inventionto provide such a shielding means.

Other objects will hereinafter appear.

In accordance with the invention there is provided a shield or braidingof tinsel thread which is woven about the conductor but insulatedtherefrom. Furthermore this tinsel braiding is closely wound at thepoint where the conductors are brought out through the braiding toprovide a conducting strand which may be grounded or connected to themetallic parts of the apparatus and which may also serve as a stay-cordto prevent any undue strain being placed upon the conductor itself.

In the drawings:

Fig. 1 discloses a receiver cord embodying the invention.

Fig. 2 is an enlarged view of a cord with parts broken away to show theconstruction thereof.

The receiver cord as shown in Fig. 2 comprises conductors 3. 4surrounded' by a flexible shield over which is placed a protectivebraiding. Each conductor consists of a plurality of conducting strands5-5 of tinsel thread. each tinsel thread consisting of a textile core 6about which is helically wound a metallic tape 7.y The strands 5 aretwisted together asshovvn and are then served with two layers 8 -8 offloss or a similar insulating material, these layers being laid with thedirection of Winding reversed. Over the servings 8-8 is placed aninsulating coatance of the cord a textile braiding 14 is y placed overthe shield 11.

In the case of a receiver cord as shown in Fig. 1, the two conductorsv 3and 4 are separated the desired distance and an additional insulatedconductor 17 of suitable length to ,connect the two receivers togetheris provided as shown, the braidings 11 and 14 being continued over theseparate branches of the cord. By means of terminals. 18-18 the variousconductors are connected to the windings of the receivers in such amanner that the two windings are joined in series. The braid`14 isdiscontinued a short distance fromthe end of the conductors as at 20 andthe conductors are brought out from the shielding braiding 11, thisbraid being continued for a short distance and closely wound so as toform a conducting strand 21 which may be connected to the metallic partsof the receiver by means of an eye member 22, thus permitting theapparatus to be grounded. By making the length of the strand-21 slightlyless than the length of the adjacent portions of the conductors, any'strain placed upon the cord is taken up by means of the strand 21, thuspreventing damage to the insulated conductors or the loosening of theconnections. l

At the opposite end of the cord (not shown) the shielding braiding l1 isalso arranged to provide a closely wound conducting strand to form aground connection and which may also be used, .if desired, as astay-cord.

By means of the flexible shielding described above, it is possible toovercome a diiiculty heretofore experienced in properly shieldingcertain types of apparatus. The construction described has the furtheradvantage of removing all strain from the conductors themselves and byserving to connect' all metallic parts to ground it provides protectionfrom all static disturbances.

What is claimed is:

1. A flexible shielded electrical conductor for attachment to pieces ofelectrical apparatus, comprising a plurality of mutually insulatedconducting strands, and a uni-potential braided conducting shieldsurrounding said conducting strands, said shield terminating inelongated portions adapted to connect to portions of the electricalapparatus to relieve mechanical strain on the conducting strands and toequalize the electrical potential of said pieces of apparatus.

2. A Shielded electrical conductor coinprising an insulated conductor, abraiding ofilexible conducting material surrounding said insulatedconductor and extending beyond the endthereof to provide a stay cord anan electrical connection between said shield and apparatus connectedwith said conductor.

3. In combination, a telephone receiver` a metallic casing therefor, apair of flexible insulated conductors connected to the receiver, andflexible means to shield said conductors, said shield consisting of agrounded braiding of tinsel strands surrounding said cond-uctorsthroughout the greater part of their length but having one end closelywound and attached to said casing to provide a stay cord for theconductors and a ground for the casing.

4. A telephone headset, comprising in combination a pair ofelectromagnetic sound reproducing devices, an insulated conductorconnecting said devices, a flexible braided shield surrounding saidconductor, said shield consisting of Woven tinsel conductors and aprotecting'braid about said shield.

5. A telephone headset, comprising in combination a pair ofelectromagnetic sound reproducing devices, an insulatedconductorconnecting said devices, a flexible braided shield surrounding saidconductor, said shield consisting of closely Woven metallic conductorsterminating in stay cords at each end for preventing any undue strainbeing placed upon said insulated conductors.

6. A telephone headset, comprising in combination a pair ofelectromagnetic sound reproducing devices, an insulated conductorconnecting said devices, a flexible braided shield surrounding saidconductor, said shield continuing beyond the ends of said insulatedconductor to provide stay cords at the telephone receiver ends of saidinsulated conductor,.and a tie cord formed by said shield at theopposite ends of said insulated conductor opposite said telephonereceiver end.

7. A receiver cord comprising a plurality of insulated conductors, aiexible electrical metallic Shield surrounding said insulatedconductors, said shield continuing beyond the ends of said conductors toprovide stay cords, and a textile protective. braiding about saidshield.

8. A telephone headset, comprising in combination a pair ofelectromagnetic sound reproducing devices, an insulated conductorconnecting said devices, an electrostatic shield completely surroundingsaid insulated conductor, said shield comprisin a plurality of iexiblebraided tinsel conc uctors and serving as a connection separate fromsaid lirst mentioned connection between said devices.

In Witness whereof, I hereunto subscribe my name this 20th day ofSeptember A. D.,

HOVARD H. GLENN.

